I am an engineer that does power design for commercial spaces. These "wellness" rooms show up a lot. They are there simply so your corporate overlords can tick a little box under "workplace atmosphere" and add it to the list of bullshit features on their website no employee ever actually uses. It's very similar to "mother's rooms", only those can be considered code compliant based on your location. Sometimes they are also called "phone rooms."

I think architects upsell them into designs to boost their self esteem.

It's a lot like when old apartment buildings gut a storage room, put a few pieces of shitty gym equipment in it, and then add "on site fitness center" to the website, and also tack a small monthly fee on your rent.

If I had a dollar for every existing office space I've surveyed that ended up just piling office supplies in them, or found them covered in 3 inches of dust... I'd probably have like $100. Not a ton, but enough to definitely make them seem ridiculous.